What are the names of months as per the Hindu calendar, and what is their significance vis-à-vis festivals or rituals?

FESTIVALS/RITUALS

1. Chaitra

The month of Chaitra is also associated with the coming of Spring, since Holi, the spring festival of colour, is celebrated on the eve of Chaitra (namely, the last day of Phalgun month). Exactly 6 days after which the festival of Chaiti Chhath is observed.

In lunar religious calendars, Chaitra begins with the new moon in March/April and is the first month of the year. The first of Chaitra – is celebrated as New Year's Day, known as Gudi Padwa in Maharashtra, Chaitrai Vishu and Ugadi in Karnataka and Andhra Pradesh.

Other important festivals in the month are; Ram Navami, the birth anniversary of Lord Ram celebrated on the 9th day of Chaitra, and Hanuman Jayanti that falls on the last day (purnima) of Chaitra.

1. Vaiśākha

The harvest festival of (Baisakhi) is celebrated in this month. Vaisakha Purnima is celebrated as Buddha Purnima or the birthday of Gautama Buddha amongst southern Buddhists or the Theravada school. Purnima refers to the Full Moon. Known in Sinhalese as Vesak, it is observed in the full moon of May

3.Jyaiṣṭha

Vat Pournima is a celebration observed in Maharashtra and Karnataka, India. It is celebrated on the full moon day (the 15th) of the month of Jyeshtha on the Hindu Calendar, which falls in June on the Gregorian Calendar. Women pray for their husbands by tying threads around a banyan tree on this day. It honors Savitri, the legendary wife of Satyavan who escaped death for her husband's life.

Snana Yatra is a bathing festival celebrated on the Purnima the Hindu month of Jyeshtha. It is an important festival of the Jagannath Cult. The deities Jagannath, Balabhadra, Subhadra, Sudarshan, and Madanmohan are brought out from the Jagannath Temple (Puri) and taken in a procession to the Snana Bedi. They are ceremonially bathed and decorated for a public audience.

Sitalsasthi Carnival is being conducted in this month on the day of Jyeshtha Shuddha Shashthi in Odisha for many centuries

1. Asadha

Guru Purnima, a festival dedicated to the Guru, is celebrated on the Purnima (Full Moon) day of the month. Prior to it Shayani Ekadashi, is observed on the eleventh lunar day (Ekadashi) of the bright fortnight.

1. Sravana

Shravana(jupaka) is considered to be a holy month in the Hindu calendar due to the many festivals that are celebrated during this time. Krishna Janmashtami, marking the birth of Krishna, falls on the 8th day after the full moon. Raksha Bandhan, the festival of brothers and sisters, is celebrated on Shraavana Poornima (Full Moon). This day in Maharashtra is also celebrated as Narali Poornima (Naral in Marathi language means coconut). In the coastal regions of Maharashtra i.e. Konkan, a coconut is offered to the sea for calming it down after the monsoon season. Fishermen now start fishing in the sea after this ceremony. Nag Panchami is also celebrated in many parts of India on the fifth day after Amavasya of Shraavana month. The snake god Nāga is worshiped. The last day of the Shraavana is celebrated as Pola, where the bull is worshiped by farmers from Maharashtra.

In TamilNadu (& also in Kerala) Aadi Amavasaya is celebrated with great importance in all temples. It is an equivalent to Mahalaya Amavasaya of north India.In Karnataka Basava Panchami is celebrated on 5th day after amavasya.

Shravani Mela is a major festival time at Deoghar in Jharkhand with thousands of saffron-clad pilgrims bringing holy water around 100 km on foot from the Ganges at Sultanganj.Shravan is also the time of the annual Kanwar Yatra, the annual pilgrimage of devotees of Shiva, known as Kanwaria make to Hindu pilgrimage places of Haridwar, Gaumukh and Gangotri in Uttarakhand to fetch holy waters of Ganges River

1. Bhādrapada or Bhādra also Proṣṭhapada

Anant Chaturdashi is a Jain religious observance is performed on the fourteenth day (Chaturdashi) of the bright fortnight (Shukla paksha) of Bhadrapad month.

Madhu Purnima (Bengali for 'honey full-moon') is a Buddhist festival celebrated in India and Bangladesh, especially in the region of Chittagong. It occurs on the day of the full moon in the month of Bhadro (August/September).

7.Asvina

Several major religious holidays take place in Ashvin, including Durga Puja (6-10 Ashvin), Dasehra (10 Ashvin) and Divali (29 Ashvin), Kojagiri festivals and Kali Puja (new moon of Ashvin),

8.Kartika

The festival of Kartik Poornima (15th day Full Moon) falls in this month, celebrated as Dev Deepavali in Varanasi. This coincides with the nirvana of the Jain Tirthankara - Mahavira and the birth of the Sikh Guru Nanak Guru Nanak Jayanti. And also, the well known festival, for the god of Sabarimalai, Ayyappan's garland festival.

9.Agrahāyaṇa

Vaikuṇṭha Ekādaśī, the Ekādaśī (i.e. 11th lunar day) of this Mārgaśīṣa month, is celebrated also as Mokṣadā Ekādaśī. The 10th Canto, 22nd Chapter of Bhāgavata Purāṇa, mentions young marriageable daughters (gopis) of the cowherd men of Gokula, worshiping Goddess Kātyāyanī and taking a vrata or vow, during the entire month of Mārgaśīṣa, the first month of the winter season (Śiśira), to get Śrī Kṛṣṇa as their husband.

Kālabhairava Aṣṭamī (or Kālabhairava Jayanti) falls on Kṛṣṇa Pakṣa Aṣṭamī of this month of Mārgaśīṣa. On this day it is said that Lord Śiva appeared on earth in the fierce manifestation (avatāra) as Śrī Kālabhairava. This day is commemorated with special prayers and rituals.

1. Pausa

The harvest festival of Pongal/Makar Sankranti is celebrated on this month.

1. Magha

Vasant Panchami, sometimes referred to as Saraswati Puja, Shree Panchami, or the Festival of Kites is a Sikh and Hindu festival held on the fifth day of Magha (in early February) marking the start of spring and the Holi season. On this day Hindus worship Saraswati, the goddess of knowledge, music, art and culture.

Ratha Saptami or Rathasapthami is a Hindu festival that falls on the seventh day (Saptami) in the bright half (Shukla Paksha) of the Hindu month Maagha. It marks the seventh day following the Sun’s northerly movement (Uttarayana) of vernal equinox starting from Capricorn (Makara).

12.Phalguna

Most parts of North India see early celebration of the famous Hindu festival Holi in this month. Holi is celebrated at the end of the winter season on the last full moon day of the lunar month Phalguna (Phalguna Purnima), which usually falls in the later part of February or March.
The Hindu festival of Shigmo is also celebrated in Goa and Konkan in the month of Phalguna. Celebrations can stretch over a month.